Satellite-based communications systems are well known. Such systems are frequently used to provide communications between a fixed terrestrial base station and widely spaced fixed or mobile subscriber units. The subscriber units might be used for voice or data communications and instances where the location, or status of a vehicle or other equipment is to be monitored, a satellite-based system ensures that communication between the fixed site terrestrial base station and the subscriber units can be maintained. Existing cellular communication networks for example do not provide cellular communications in all portions of the country. Similarly, land line communications may not be available either.
A satellite communications system can enable automatic and remote collection of data from utility meters or other equipment interfaced to subscriber communication units that can communicate with a satellite. Data collected by a remote subscriber communication unit can be uploaded to a satellite. The satellite can thereafter download the data it collected from the subscriber unit to a terrestrial base station from which the data can be passed to a processing center. A subscriber communicator that collects data from utility meters, and the like is preferably inconspicuous, weatherproof, and inexpensive enough such that the device would not be damaged by vandalism, weather or be so prohibitively costly as to make its commercial effectiveness questionable.
A problem with communicating with an overhead satellite, is of course that the subscriber communicator must be able to send and receive radio frequency signals to and from the satellite. In addition to a radio transmitter sufficiently robust to produce a signal, such a subscriber unit must of course have a radiating device that can permit such communications to take place. Improving antenna performance, particularly spatial coverage of the radiation pattern, in the process can reduce the output power that a transmitter must develop. In applications such as residential data collection, an antenna is preferably concealed to reduce the likelihood of being damaged by vandalism or the environment.
A low profile antenna which can be hidden and which will produce acceptable gain in the frequency bands required to communicate with the satellite would facilitate the commercial viability of satellite based data collection systems.
Accordingly it is an object of the present invention to provide a low profile, concealed antenna system for use with a low earth orbit satellite data system.